This invention generally relates to the art of fiber optic connectors and, particularly, to a fiber optic connector which includes a pair of shutter members, and a connector assembly which is particularly dimensioned to prevent alignment pins of one connector from damaging an internal mating face of a second connector.
Fiber optic connectors of a wide variety of designs have been employed to terminate optical fiber cables and to facilitate connection of the cables to other cables or other optical fiber transmission devices. A typical optic fiber connector includes a ferrule which mounts and centers an optical fiber or fibers within the connector. The ferrule may be fabricated of such material as ceramic. A ferrule holder or other housing component of the connector embraces the ferrule and may be fabricated of such material as molded plastic. A spring may be disposed within the housing or ferrule holder such that the ferrule is yieldably biased forwardly for engaging another fiber-mounting ferrule of a mating connecting device.
A plurality of fiber optic connectors often are mated in an adapter with another connector or connectors, with the adapter aligning the fibers to provide low insertion losses. The adapter couples the mating connectors together so that their encapsulated fibers connect end-to-end. The adapter may be an in-line component, or the adapter can be designed for mounting in an opening in a panel, backplane, circuit board or the like.
Various problems are encountered when terminating optical fibers in fiber optic connectors versus terminating electrical conductors in electrical connectors, when situations arise wherein a fiber end of an xe2x80x9cactivexe2x80x9d fiber optic connector is exposed. A typical situation might arise when one of the fiber optic connectors at one end of an adapter is removed, leaving the other xe2x80x9cactivexe2x80x9d fiber optic connector or connectors in the adapter.
In particular, an exposed fiber end may be damaged by adverse environmental hazards, and the accumulation of dust and dirt may impair the optical transmission capabilities of the fiber. Another very important problem is to protect an operator""s eyes from dangerous light beams from the exposed-end of an active optical fiber. For instance, an operator""s eyes may be damaged from dangerous light beams exiting an unprotected receptacle or adapter.
Heretofore, dust covers, end caps or spring-loaded shutter members have been used to close an open end of an adapter to, thereby, cover the exposed fiber ends to protect the fiber ends from adverse environmental hazards and to prevent light energy from the fiber ends from exiting the adapter. One such spring-loaded shutter member is pivotally mounted on the adapter adjacent the open end thereof and is pivotally movable to close and open the open end. The shutter member extends across the optic axis of the connector/adapter assembly when the shutter member is closed. The shutter member may be pivotable away from the optic axis to its open condition.
In some connector assemblies, a pair of opposing shutter members are used, versus a single shutter member. The pair of shutter members are pivotally mounted at opposite sides of the connector receptacle, and the use of a pair of opposing shutter doors has a number of advantages. First, the two shutter members save considerable axial space which otherwise would be required to accommodate the full pivoting action of a single shutter member which would be approximately twice the size of a pair of shutter members. Second, it is easier to open the two smaller shutter members because smaller springs can be provided. When a mating connector has alignment pins, the pins generally are at the center of the connector and, thereby, most forces are applied near the edges of the pair of shutter members, whereas with a single shutter member a large force is required on one side of the centerline than the other side. Third, the wiping surface of either of the pair of shutter members is one-half the wiping surface of a single shutter member. With the single shutter member, dust collected on the outside of the shutter member is carried all the way into the interface area between the connectors. With a pair of shutter members, any dust which accumulates on the outer surfaces thereof will be deposited away from the mating interface rather than being carried further inwardly.
However, the use of a pair of opposing shutter members continue to create problems in being able to completely close an open end of a receptacle without causing binding between the shutter members. The present invention is directed to solving this problem by a simple arrangement whereby one shutter member is shorter than the other shutter member and, thereby, the shorter shutter member closes before the longer shutter member and there can be no binding.
The invention herein is directed to solving other problems in mating such fiber optic connectors by providing specific dimensional relationships between a receptacle and a plug of a connector assembly to prevent alignment pins on the plug from damaging the mating interface within the receptacle.
An object, therefore, of the invention is to provide a new and improved fiber optic connector assembly of the character described.
According to one aspect of the invention, a connector receptacle is provided for receiving a fiber optic connector along an optic axis. The receptacle includes a housing having an open end for receiving the fiber optic connector inserted thereinto on the optic axis. A pair of shutter members are pivotally mounted on the housing at opposite sides of the open end for pivotal movement toward and away from each other toward and away from the optic axis to close and open the open end. One of the shutter members is shorter than the other shutter member in a direction radially of the axis so that the one shutter member closes before the other shutter member and, thereby, prevents binding therebetween.
In the exemplary embodiment of the invention, the shutter members are generally planar and rectangular for closing a generally rectangular open end of the housing. An inner edge of the longer shutter member overlaps an inner edge of the shorter shutter member when the shutter members are closed. A spring is operatively associated between each shutter member and the housing to bias the respective shutter member toward its closed positions. The springs have generally equal spring constants to apply a generally equal spring force on each shutter member.
According to another aspect of the invention, a fiber optic connector assembly includes a first connector having a housing with a receptacle defining an optic axis. A bottom of the receptacle defines a mating face with a pair of transversely spaced pin-receiving guide holes. A second connector includes a housing forming a plug insertable into the receptacle of the first connector on the optic axis. The second connector has a pair of transversely spaced alignment pins projecting axially from the plug for insertion into the guide holes in the mating face at the bottom of the receptacle of the first connector. The plug and the receptacle have respective cross-dimensions such as to provide a sufficiently close fit, and the receptacle is of sufficient depth in relation to the length of the plug and the projecting alignment pins, to prevent the alignment-pins from engaging the mating face at the bottom of the receptacle rather than entering the guide holes in the mating face.
According to still another aspect of the invention, an elongated guide rib is provided on one of the outside of the plug of the second connector or the inside of the receptacle of the first connector, insertable into an elongated groove in the other of the outside of the plug or the inside of the receptacle when the plug is inserted into the receptacle. The rib and the groove extend generally parallel to the optic axis. The rib has a sufficiently close fit in the groove, and the rib and groove have sufficient lengths in relation to the length of the alignment pins, to prevent the alignment pins from engaging the mating face at the bottom of the receptacle rather than entering the guide holes in the mating face.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.